New images show what is likely to be melted nuclear fuel hanging from inside one of Japan's wrecked Fukushima reactors, a potential milestone in the cleanup of one of the worst atomic disasters in history.
Tokyo Electric Power Co. Holdings Inc., Japan's biggest utility, released images on Friday showing a hardened black, grey and orange substance that dripped from the bottom of the No. 3 reactor pressure vessel at Fukushima, which is likely to contain melted fuel, according to Takahiro Kimoto, an official at the company. The company sent a Toshiba-designed robot, which can swim and resembles a submarine, to explore the inside of the reactor for the first time on July 19.
"Never before have we taken such clear pictures of what could be melted fuel," Kimoto said at a press briefing that began at 9 p.m. Friday in Tokyo, noting that it would take time to analyze and confirm whether it is actually fuel. "We believe that the fuel melted and mixed with the metal directly underneath it. And it is highly likely that we have filmed that on Friday."
(Score: 2) by RamiK on Monday July 24 2017, @07:11AM (5 children)
Tsunamis are part of cascading seismic events. The 1993 report (which deals with Station Blackouts) asses everything should be fine as long as grid power is restored within a few hours since the on-site batteries are good for 4 hours which is enough time to start the emergency diesel generator.
However, as the committee chairman commented on protocol, those weren't reasonable assumptions. Even disregarding direct earthquake damage to the plant, although there weren't any past grid cutoff incidents extending over 30min in Japan, anyone with a lick of sense would know those can, and will happen eventually. They even had multiple separate codes for equipment like the emergency diesel generators that required continuous operation precisely because separate regulatory bodies assessed days and even weeks worth of potential localized power losses. And any power loss is unacceptable when it takes spent fuel rods a decade to cool off in circulating water pools, let alone partially spent rods in standing water...
compiling...
(Score: 1) by khallow on Monday July 24 2017, @09:31AM
(Score: 1) by khallow on Monday July 24 2017, @09:53AM (3 children)
The New York Times wrote a story where they claim that the lessons [nytimes.com] of a western Japan earthquake in 1993 should have been learned (though not why that was supposed to be a lesson - should every nuclear plant in the world near water engineer for 10 meter high tsunami?). Once again, no actual research cited until the above mentioned 2002 paper.
If there really was research from 18 years ago, you'd think the variety of media sources out there would have cited it by now.
(Score: 2) by requerdanos on Monday July 24 2017, @01:52PM (2 children)
This isn't a zomg-tsunami, but it's a specific related concern (basement flooding risk) unearthed from more than 18 years prior:
- Japan Times, 14 July 2011 [japantimes.co.jp], emphasis added.
(Score: 1) by khallow on Monday July 24 2017, @10:38PM (1 child)
(Score: 2) by requerdanos on Monday July 24 2017, @11:59PM
I haven't personally researched that, but they were Pretty Darn Visible, per wikipedia:
https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster#1991:_Backup_generator_of_Reactor_1_flooded [wikipedia.org]